It certainly would be possible, though I am not sure how they are doing it. More likely there is a server constantly running and backing up data, that people ca

It certainly would be possible, though I am not sure how they are doing it. More likely there is a server constantly running and backing up data, that people can join and make edits in real-time. EDIT: After looking at the website a bit more, it appears that there is a sort of VCS that is managed by the admins. Users make changes and send them to the admins, and if they are OK then they get merged into the main world.